Products having general formula (I) are among the most important starting materials used to obtain certain molecules having interesting therapeutic properties.
Oxidation of an alkyl lactate to form the corresponding alkyl pyruvate is known either in the vapour phase using air or oxygen or in the presence of a metallic catalyst such as platinum, silver or vanadium, deposited if necessary on aluminium at temperatures of between 190.degree. C. and 500.degree. C., or in the liquid phase by potassium permanganate alone or mixed with copper II sulphate (see Beilsteins Handbuch der Organischer Chemie, Vol. III, 4th supplement, p. 1513).
These known processes are not entirely satisfactory, however. In particular, the catalytic oxidation reactions, although selective, are rarely complete and the chemical oxidation reactions, although complete, are either nonselective or produce substantial quantities of mineral salts.
As a result, isolation of the desired product at the end of the reaction is laborious and costly and, further, it is difficult to separate the untransformed alkyl lactate from the corresponding alkyl pyruvate by distillation given their very similar boiling points.